Monocytes have been implicated in the pathogenesis of atherosclerosis. The binding of monocytes to endothelial cells which line blood vessel walls is an early event in the development of atherosclerotic lesions. The mechanism by which the monocytes bind to the endothelial cells is unknown. Sites of injury have shown evidence of monocyte adhesion. Therefore, for the prevention and treatment of atherosclerosis and other diseases which involve the invasion of tissues surrounding blood vessels by monocytes, it is necessary to lessen or prevent the adherence of monocytes to endothelial cells. In addition, a decrease in monocyte adherence to endothelial cells may similarly decrease inflammation.
The method of this invention utilizes cytokines to induce a monocyte adhesion protein to the surface of endothelial cells. Cytokines are protein cell regulators, also known as lymphokines, monokines, interleukins and interferons. Cytokines are low molecular weight secreted proteins which are involved in immunity and inflammation, where they regulate amplitude and duration of immunological response. They are usually produced transiently and locally, and interact with high affinity to cell surface receptors specific for each cytokine or cytokine group. Their cell surface binding leads to changes in cellular RNA and protein synthesis culminating in alterations of cell-function. In the present invention, the monocyte adhesion protein induced to the cell surface by the cytokines forms a complex with a monoclonal antibody specific for the protein. As a result, monocyte adherence to endothelial cells is decreased.
U.S. Pat. No. 5,011,778 to Newman, et al. entitled "Monoclonal Antibodies Directed to IL-1 Activated Endothelial Cells and Medicaments Employing the Monoclonal Antibodies", ("the Newman Patent") discloses monoclonal antibodies which bind to proteins on the surface of IL-1 activated endothelial cells, which antibodies do not bind significantly to normal resting endothelial cells and do not bind significantly to normal resting IL-1 activated epidermal keratinocytes or resting IL-1 activated fibroblasts. The monoclonal antibodies disclosed in the Newman Patent are indicated for use in therapeutic compositions for blocking inflammatory responses associated with activated endothelial cells.
The Newman Patent discloses four specific monoclonal antibodies designated IE7, 2G7, 7A9 and 3A2. Monoclonal antibody IE7 blocks the binding of T-cells, B-cells, NK cells and monocytes to proteins on the surface of IL-1 activated endothelial cells. Monoclonal antibody IE7 binds to the protein VCAM. Further, proteins to which monoclonal antibody IE7 bind have, under non-reducing conditions on SDS-PAGE, a major band at 99 kD and a minor band at 97 kD. Further, the IE7 monoclonal antibody binds to proteins on the surface of IL-1-treated endothelial cells which proteins have chronic expression (i.e., have maximal expression on the surface of the endothelial cells for 72-96 hours).
Monoclonal antibody 2G7 of the Newman Patent blocks the binding of T-cells, B-cells and monocytes to proteins on the surface of IL-1-treated endothelial cells. Monoclonal antibody 2G7 also binds to the protein VCAM. Further, monoclonal antibody 2G7 reacts with proteins which, under non-reducing conditions on SDS-PAGE, have a major band at 99 kD and a minor band at 87 kD. In addition, monoclonal antibody 2G7 binds to proteins on the surface of IL-1-treated endothelial cells, which proteins have chronic expression (i.e., have maximal expression for 72-96 hours).
Monoclonal antibody 7A9 of the Newman Patent blocks the binding of granulocytes and monocytes to proteins on the surface of IL-1-treated endothelial cells. Monoclonal antibody 7A9 binds to the protein ELAM. Further, the 7A9 monoclonal antibody binds to proteins which, under non-reducing conditions on SDS-PAGE, show a band at 90 kD. In addition, the 7A9 monoclonal antibody binds to proteins on the surface of IL-1-treated endothelial cells which proteins have chronic expression (i.e., have maximal expression for 72-96 hours).
Monoclonal antibody 3A2 of the Newman Patent binds to proteins which, under non-reducing conditions on SDS-PAGE, show a major band at 177 kD and a minor band at 57 kD. Further, the 3A2 monoclonal antibody binds to proteins which have acute expression on the surface of IL-1-treated endothelial cells (i.e., the expression of such proteins decreases and disappears by 24 hours).
The monoclonal antibodies of the Newman Patent bind to the proteins VCAM and ELAM, which proteins are induced to the surface of endothelial cells with cytokines. The monoclonal antibody of the present invention does not bind to either VCAM or ELAM. Instead, the monoclonal antibody binds to a different monocyte adhesion protein.
To date, no protein has been discovered, purified or induced to the surface of endothelial cells wherein the forming of a complex between such protein and a monoclonal antibody for such protein prevents the adherence of monocytes to such endothelial cells without preventing the adherence of T-cells, B-cells, NK cells, granulocytes, lymphocytes or other white blood cells to such endothelial cells, thereby more effectively reducing monocyte invasion of blood vessels and diseases related thereto. The present inventors have induced a protein to the surface of endothelial cells and have raised monoclonal antibody to such protein. The formation of a complex between such protein and monoclonal antibody on the surface of endothelial cells results in the prevention of monocyte adherence to such endothelial cells, but not the adherence of other white blood cells. It is believed that this specificity for monocytes is advantageous in the treatment and prevention of monocyte induced or oriented inflammation and diseases.
It is an object of this invention to provide a method for reducing monocyte adherence to endothelial cells lining blood vessels.
It is another object of this invention to provide a method for reducing monocyte invasion of blood vessels surrounding tissues.
It is a further object of this invention to provide a method for reducing diseases related to monocyte adherence to endothelial cells lining blood vessels and invasion of blood vessels surrounding tissues.
It is still a further object of this invention to induce a monocyte adhesion protein to the surface of endothelial cells and to produce a monoclonal antibody thereto wherein the formation of a complex between such protein and monoclonal antibody specifically blocks the adherence of monocytes to said endothelial cells but does not block the adherence of other white blood cells to said endothelial cells.
It is another object of this invention to produce a monoclonal antibody specific for proteins recognized by monocytes but not recognized by other white blood cells.